English Language & Usage: Multi-Layered Discourse Room

MετάEd

12:05 AM

If God dropped acid, who would He see?

crl

12:28 AM

@Robusto yes, I know, it's some test code, I'm porting this in react where it's different output.jsbin.com/pajabe

worst holocaust in history is probably the one caused by tobacco

Robusto

@crl You should give the dragged item a background so it's more obvious.

crl

oh right :)

they all have backgrounds for the moment, but just for tests, will set something else, good idea

Robusto

@crl I also don't like having huge object literals like that. I prefer to create an object with a null prototype using Object.create(null) and then assigning members to it as I go along. It's much easier to read and debug. You always know what level you're at in the hierarchy.

You wind up with the same thing, but it's just easier to handle.

The this binding is also more obvious.

crl

yes, I see, I don't feel well writing this outside a class for some reason :)

Robusto

You can still write the class. Just put the properties in the constructor and the methods on the prototype.

crl

12:43 AM

yep I'll need to use ES6 class anyway, for doing some inheritance between multiple templates

you can do inheritance with ES5 right too? but it's a bit ugly?

Robusto

It's not "ugly" . . .

crl

oh I might try

Robusto

E6 has some nice features, but they're usually stuff you only need if you want to show off. They're an incremental improvement at best.

crl

function A () {this.name='A'; this.foo = function(){console.log(this.name};}

now how to make a function B with name 'B' extend A?

Robusto

You can't the way you just did it.

function A (foo) {
  this.name = 'A';
  this.foo = foo;
}
A.prototype.bar = function() { console.log(this.name); }

crl

12:47 AM

can you show me how? prototypes have always been obscure to me, ah ok^

and for B? that would inherit methods of A with some differences

Robusto

That's a little longer. I'll show you, but I hate typing in this little window. Gotta switch out and do it in a text editor.

Then I'll paste it here.

crl

thanks

Robusto

function B (foo, baz) {
  A.call(this, foo);
  this.baz = baz;
}
B.prototype = Object.create(A.prototype);
B.prototype.constructor = A;
B.prototype.otherMethod = function(){ /* do stuff */ }

@crl ^

Get used to putting a class's methods on the prototype instead of in the constructor. It uses about 90% less memory and is even faster.

crl

ok

Robusto

So our B class is a subclass of A. A bit trickier than classical inheritance, but actually quite expressive.

crl

12:56 AM

the inheritance is done with A.call(this, foo);?

Robusto

That's the constructor part of it.

The line following the constructor assigns A's prototype to B.

crl

constructor is a special property right?

Robusto

Well, it's not really a property . . .

You've never used constructors before?

I thought Java and C# both had those.

If you want I can send you a PPT presentation I did on the JavaScript prototype that goes over some of this stuff.

crl

yes, the public SomeClass(int a, int b){...}

Robusto

Yeah, so I don't understand why you ask me if the constructor is a property.

crl

1:02 AM

yep would be good

.prototype is a special property on the a function right?

Robusto

Well . . . very special.

crl

why didn't you do B.constructor directly?

Robusto

@crl I did.

That's as direct as it gets.

crl

B.constructor = A; instead of B.prototype.constructor = A;

and B.otherMethod= instead of B.prototype.otherMethod=

Robusto

Oh, I see what you mean. No, that's not how it works. In classical inheritance, you always have a constructor in the class, right? And you call the superclass from the constructor?

crl

1:06 AM

I guess prototype is to make this work

Robusto

Among other things. It's the secret sauce.

crl

@Robusto yes super(args)

super(this), Java's a bit far now

Robusto

var b = new B ( 'ten', {name:'baz',amount:0} );
b.instanceOf(A); // returns true
b.name; // 'ten'

crl

ok I'll test it, thanks a lot, (2am gotta sleep a bit :)

see you tomorrow or later

Robusto

laterz

OH, hey, I messed up the instanceof operator, sorry

@crl Should be b instanceof A

Had a brain cramp there.

I also missed up the logic for the name. I'm tired too. But you get the idea.

The name is hardcoded to 'A' in the A constructor.

cornbread ninja 麵包忍者

2:29 AM

@Mitch may he rest in peace.

Kanth

6:15 AM

Good, coding is also being discussed here though this room is about English language.

crl

8:12 AM

@Kanth hehe, why not

user685252

You can grow new brain cells. Here's how

crl

@Robusto ok getting better ES5 inheritance, they do the same way here, classes indeed do the same, but it's a bit clearer imo es6fiddle.net/igxdzagt

I wish there were something like Object.assign (object merging) but for functions, for doing inheritance simply (but maybe it's missing some points like passing this, still not sure to get it fully :) )

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English Language & Usage: Multi-Layer…